<div id="twelve columns" class="panel">
    <table width="100%">
      <thead>
        <tr>
        <?php
           $keys= array_keys($alumnos[0]);
           //print_r($keys) ;
           
           for($i=0;$i<count($keys);$i++){
             echo "<th> ".$keys[$i]."</th>";
           }
        ?>
        </tr>
      </thead>
      <tbody>
        <?php
         foreach ($alumnos as $item) {
           //echo "<td> <input type='checkbox' name='chk_id[]' value=''> </td>";
           foreach ($item as $row) {
              echo "<td>".$row."</td>";
           }
         }
         ?>
      </tbody>
      
    </table>